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PHOTOSENSITIZATION OF MITOCHONDRIA BY LIPOSOME‐BOUND PORPHYRINS
Author(s) -
Ricchelli Fernanda,
Gobbo Silvano,
Jori Giulio,
Moreno Giuliana,
Vinzens Françoise,
Salet Christian
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb04903.x
Subject(s) - cardiolipin , liposome , hematoporphyrin , photosensitizer , mitochondrion , chemistry , phosphatidylcholine , membrane , biophysics , singlet oxygen , cytosol , inner mitochondrial membrane , digitonin , biochemistry , oxygen , photochemistry , phospholipid , biology , photodynamic therapy , organic chemistry , enzyme
We have compared the photodynamic activities of hematoporphyrin (HP) and protoporphyrin (PP) on isolated rat liver mitochondria by measuring the decline of the respiratory control ratio (RCR) after irradiation at 365 nm. Before addition to the respiratory mcdium, the dyes were dissolved in phosphate‐buffered saline (PBS) or incorporated into unilamellar liposomes of dipalmitoyl‐phosphatidylcholine (DPPC), sometimes enriched with cholesterol (Chol) or cardiolipin (Card), which are naturally present in mitochondrial membranes. Chol and especially Card strongly increase the porphyrin uptake by mitochondria. In all experimental conditions, PP is taken up by mitochondria to a higher extent than HP. Nevertheless, under conditions giving the same amount of mitochondriabound dye, HP is a morc efficient photosensitizer than PP. As the efficiency of singlet oxygen production has been shown to be equivalent for the two porphyrins in monomeric state, the resulting photobiological effects are explained in terms of different localization of HP and PP in the mitochondrial membrancs. In particular, HP preferentially localizes in the protein‐rich polar domains of the inner mitochondrial membrane, whereas PP dissolvcs in the lipid regions of the mcmbrancs.